1. Field of the Invention
The present invention relates to a resistor device, and more particularly to a current sensing resistor with improved mechanical strength and better electrical performance.
2. Description of the Related Art
Current sensing resistors such as shunt resistors are known in the art. A current sensing resistor, when serially connected to a load and applied current thereto, results in a voltage drop which may be measured and referred to estimate the current intensity.
Current sensing resistors are used in various kinds of electrical equipment. Typically, a current sensing resistor comprises a metal plate resistor having a resistor body consisting of a metal material, which has a small temperature coefficient of resistance, and a pair of electrodes consisting of a metal material, which has high electrical conductivity, connected to both ends of the resistor body.
Typically, surface soldering processes are utilized in the manufacturing of the current sensing resistors. This method may cause the displacement of the detection terminal under the high temperature environment, resulting in variation of the resistance value and loss of detection accuracy.
Another method is coating solder on the electrodes on both sides of the current sensing resistor, then connecting to a printed circuit board (PCB) by surface mount technique (SMT). However, the high-temperature operation condition will lead to molten solder and resistance variation. There is also the risk of short circuiting the surrounding electronic components by directing heat to the circuit board.